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Properly handle relocated jump tables in the live recompiler

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This commit is contained in:
Mr-Wiseguy 2024-12-29 19:07:47 -05:00
parent 75f2abdb7d
commit f09587bf1f
7 changed files with 32 additions and 9 deletions
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22
LiveRecomp/live_generator.cpp
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@ -1512,7 +1512,7 @@ void N64Recomp::LiveGenerator::emit_branch_close() const {
context->cur_branch_jump = nullptr;
}
void N64Recomp::LiveGenerator::emit_switch(const JumpTable& jtbl, int reg) const {
void N64Recomp::LiveGenerator::emit_switch(const Context& recompiler_context, const JumpTable& jtbl, int reg) const {
// Populate the switch's labels.
std::vector<std::string> cur_labels{};
cur_labels.resize(jtbl.entries.size());
@ -1531,7 +1531,25 @@ void N64Recomp::LiveGenerator::emit_switch(const JumpTable& jtbl, int reg) const
sljit_emit_op1(compiler, SLJIT_MOV, Registers::arithmetic_temp1, 0, SLJIT_MEM1(Registers::ctx), get_gpr_context_offset(reg));
// Subtract the jump table's address from the jump target to get the jump table addend.
// Sign extend the jump table address to 64 bits so that the entire register's contents are used instead of just the lower 32 bits.
sljit_emit_op2(compiler, SLJIT_SUB, Registers::arithmetic_temp1, 0, Registers::arithmetic_temp1, 0, SLJIT_IMM, (sljit_sw)((int32_t)jtbl.vram));
const auto& jtbl_section = recompiler_context.sections[jtbl.section_index];
if (jtbl_section.relocatable) {
// Make a dummy instruction context to pass to `load_relocated_address`.
InstructionContext dummy_context{};
// Get the relocated address of the jump table.
uint32_t section_offset = jtbl.vram - jtbl_section.ram_addr;
// Populate the necessary fields of the dummy context and load the relocated address into temp2.
dummy_context.reloc_section_index = jtbl.section_index;
dummy_context.reloc_target_section_offset = section_offset;
load_relocated_address(dummy_context, Registers::arithmetic_temp2);
// Subtract the relocated jump table start address from the loaded address.
sljit_emit_op2(compiler, SLJIT_SUB, Registers::arithmetic_temp1, 0, Registers::arithmetic_temp1, 0, Registers::arithmetic_temp2, 0);
}
else {
sljit_emit_op2(compiler, SLJIT_SUB, Registers::arithmetic_temp1, 0, Registers::arithmetic_temp1, 0, SLJIT_IMM, (sljit_sw)((int32_t)jtbl.vram));
}
// Bounds check the addend. If it's greater than or equal to the jump table size (entries * sizeof(u32)) then jump to the switch error.
sljit_jump* switch_error_jump = sljit_emit_cmp(compiler, SLJIT_GREATER_EQUAL, Registers::arithmetic_temp1, 0, SLJIT_IMM, jtbl.entries.size() * sizeof(uint32_t));